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'Catastrophic flooding' hits Houston after Harvey's heavy downpour

Rescuers in Houston answered hundreds of desperate calls for help on Sunday as floodwaters from the remnants of Hurricane Harvey climbed high enough to fill the second floors of homes and stranded families were urged to seek refuge on their rooftops. Areas south of the city appeared to be hardest-hit. Earlier in the day, the National Weather Service said the "catastrophic flooding" in Houston was "expected to worsen."

Rescuers in Houston answered hundreds of desperate calls for help on Sunday as floodwaters from the remnants of Hurricane Harvey climbed high enough to fill the second floors of homes and stranded families were urged to seek refuge on their rooftops. Areas south of the city appeared to be hardest-hit. Earlier in the day, the National Weather Service said the "catastrophic flooding" in Houston was "expected to worsen." Alexa Ard / McClatchy

Rescuers in Houston answered hundreds of desperate calls for help on Sunday as floodwaters from the remnants of Hurricane Harvey climbed high enough to fill the second floors of homes and stranded families were urged to seek refuge on their rooftops. Areas south of the city appeared to be hardest-hit. Earlier in the day, the National Weather Service said the "catastrophic flooding" in Houston was "expected to worsen." Alexa Ard / McClatchy

Are sharks and alligators swimming the streets of Houston?

Photos purporting to show sharks and alligators swimming flooded Houston streets are running rampant on social media. Are they real?

Harvey, which made landfall Friday as a Category 4 hurricane and then lingered just off the coast as a drenching tropical storm, sent devastating floods pouring into Houston on Sunday. The rising water forced a mass evacuation of parts of the city and overwhelmed rescuers who could not keep up with constant calls for help.

But the thousands of real photos of actual flooding and devastation in Houston don’t appear to be enough for some people, who are spreading bogus photos online.

One popular photo said to show a shark swimming beside a vehicle in Houston appears to be fake, possibly dating back several years. The photo first appeared in 2011 when Hurricane Irene hit Puerto Rico, then resurfaced in 2012 during Hurricane Sandy.

It also made appearances during 2015 flooding in Houston and South Carolina, reports The Daily Beast. In 2011, The Washington Post reported the photo appeared to lift the image of a shark from a shot of a shark lurking behind a kayak in a 2005 issue of Africa Geographic.

Others are posting photos said to show alligators swimming or otherwise hanging out on Houston streets. Even Katie Couric fell for one.

Look who wandered into my friend's Houston 'hood Thinking about everyone affected by Harvey and they r safe pic.twitter.com/BTuGLACiqg

While this particular photo was shot in Houston in April, not during Tropical Storm Harvey, city officials are warning residents to beware of alligators, so it’s not beyond the realm of possibility that some alligator photos could be real.

A note to people who are waking up to floodwaters:If your house is flooded, turn off your electricity breaker.If you...